Juggler vs Montage — The runtime for agentic user interfaces: Features, Pricing & Which Is Better (2026)
A side-by-side comparison of Juggler and Montage — The runtime for agentic user interfaces — features, pricing, and ideal use cases — to help you decide which AI tool fits your workflow.
Juggler
Julian Storer
A native desktop workbench for AI coding agents with branching conversation trees, inspectable tool calls and editable context.
Key features
- Branching Conversation Trees: Fork the session at any point, recursively, so competing approaches and tangents run side by side without polluting the main context.
- Miller Column Navigation: A Finder-style column layout lays out tool calls, item properties and nested sub-threads for long reading and editing sessions.
- Transaction Inspector: Open any model transaction to see the assembled system prompt, messages, tool definitions, output, token use, timing and stop reason.
- The Context Surgeon: Fold history into a new thread, move or copy items between branches, expand a branch back into its parent, and undo structural changes.
- Local or Remote Sessions: Run the desktop app locally or the headless binary on the machine holding the code, then attach from the app, a browser or a phone.
- Durable Sessions: Sessions are stored on disk as live-synced Yjs documents, so quits, relaunches and dropped connections do not lose the conversation.
- Automatic Context Sizing: Juggler measures the full request before each call, reserves room for the answer and compacts older history before limits become an error.
- Inspectable MCP Tools: Follow an MCP handoff end to end - schema offered, arguments generated, approval, result and errors - with server status, logs and per-tool filtering.
- JavaScript Extension SDK: Context items, LLM loop strategies, slash commands, viewers and Pinboard tabs are extensions you can fork or replace, under a permissive Apache-2.0 SDK.
Best for
- Exploring Competing Fixes: Branch a thread into two sub-threads to try different approaches to the same bug and compare results before committing.
- Auditing Agent Behavior: Inspect exactly what the model received and returned when an agent makes a surprising edit to the codebase.
- Remote Development: Run the server on a dev box or GPU machine where the repository lives and drive the same live session from a laptop or browser.
- Long Refactors: Keep a multi-hour session alive across quits and reconnects, with the agent paused awaiting approval for its next step.
- Provider Comparison: Drive Claude Code, Codex, Copilot, Gemini and local Ollama models through one interface to compare behavior on the same task.
- Custom Tooling: Write JavaScript extensions that add slash commands, file viewers or new LLM loop strategies to the workbench.
M
Montage — The runtime for agentic user interfaces
Montage
A model-agnostic SDK that renders agentic, interactive UIs, hydrates artifacts faster, and reduces token usage across underlying models.
Key features
- Model-agnostic SDK: A single SDK and runtime that works with any underlying model provider, enabling developers to render agentic UI components without locking into a specific LLM.
- Agentic UI Rendering: Renders rich, interactive components (agentic widgets) that encapsulate agent behavior, state, and UI in a reusable format for web applications.
- Faster Hydration: Optimized client/server hydration flow to initialize interactive artifacts quickly, reducing perceived latency for end users.
- Token Usage Reduction: Built-in optimizations for prompt/state management that cut token usage across models, lowering operational costs and improving efficiency.
- Stateful Artifact Management: Manages and persists the state and lifecycle of interactive artifacts and their events, simplifying developer handling of agent-driven UI.
- Seamless Front-end Integration: Designed to integrate with common front-end workflows and frameworks, allowing easy embedding of agentic interfaces into existing apps.
- Model Swapping and Fallbacks: Enables switching or combining different underlying models without reauthoring UI logic, supporting fallbacks and provider-agnostic strategies.
- Developer Tooling: Provides developer-oriented APIs and runtime controls to debug, test, and tune agentic components and their interactions.
- Single SDK to render rich, interactive agentic UI components
- Runtime that hydrates interactive artifacts faster
- Reduces token usage across underlying models
- Model-agnostic operation that works with any underlying model
- Focus on rendering agentic interfaces and interactive components
Best for
- Embedding conversational, agent-driven widgets in web apps to handle complex, interactive user workflows without rebuilding front-end UI each time.
- Prototyping agentic interfaces quickly using the single SDK to iterate on UI/agent behavior while swapping underlying models for evaluation.
- Reducing LLM operational costs by leveraging Montage’s prompt and state optimizations to cut token usage across responses and background context.
- Hydrating server-rendered interactive artifacts on the client for faster startup and seamless handoff from server logic to agent-driven interactions.
- Integrating multiple model providers and failover strategies so applications can route requests to different models without changing UI code.
- Managing long-lived, stateful agent interactions (e.g., multi-step assistants or tool-using agents) with built-in lifecycle and state management.
- Build interactive agentic user interfaces with a single SDK
- Embed agent-driven UI components into applications while minimizing token costs
- Hydrate and rehydrate interactive artifacts quickly for responsive UX
- Integrate agentic UI rendering on top of different underlying language models